Ion implantation is a process of introducing dopants or impurities into a substrate via bombardment. Ion implantation systems (“ion implanters”) may comprise an ion source and a substrate stage or process chamber, housing a substrate to be implanted. The ion source may comprise a chamber where ions are generated. Beamline ion implanters may include a series of beam-line components, for example, a mass analyzer, a collimator, and various components to accelerate or decelerate the ion beam.
A useful function of an ion implanter beamline is to separate ions of different masses so that an ion beam may be formed having the desired ions for treating the work piece or substrate, while undesirable ions are intercepted in a beamline component and do not reach the substrate. In known systems, this mass analysis function is provided by an analyzing magnet, which component bends a beam of ions that all have the same energy in a curve whose radius depends on the ion mass, thus achieving the required separation. Magnets of this kind, however, are large, expensive and heavy and represent a significant fraction of the cost and power consumption of an ion implanter.
For relatively lower energy ion implantation, such as energy below approximately 50 keV, compact ion beam systems have been developed. These ion beam systems may include a plasma chamber acting as ion source, and placed adjacent a process chamber, housing the substrate to be implanted. An ion beam may be extracted from the plasma chamber using an extraction grid or other extraction optics to provide an ion beam to the substrate, with a desired beam shape, such as a ribbon beam. In these latter systems, mass analysis may be omitted because of size/space considerations for installing a magnetic analyzer, as discussed above, as well as cost. Thus, the use of such compact ion beam systems may be limited to applications where purity of implanting species is not a strict requirement.
With respect to these and other considerations, the present disclosure is provided.